对称非各向同性体大地电磁法二维异常特征

doi:10.11720/wtyht.2019.1266

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Abstract

Lots of observational data have indicated that anisotropic physical properties are common in rocks in the depth. This requires the construction of anisotropic models to obtain a true reflection of the underground medium. The basis of the present study is a review of previous research results and an investigation of the electrical properties of a layered medium representing actual geological conditions. For a symmetrical anisotropic body, an anisotropy coefficient is proposed, together with an equation for the variation of the Earth's electromagnetic field regarded as two-dimensional. Finally, a finite element simulation of a symmetrical anisotropic body is described. The finite element calculation results are compared with finite difference results to verify the accuracy of the FE program. Three sets of model conditions are considered: (1) fixed anisotropy coefficient and different dip angles, showing the effect of dip angle on an anisotropic body; (2) fixed dip angle and different anisotropy coefficients, showing the effect of the anisotropy coefficient on an anisotropic body; (3) different dip angles and different anisotropy coefficients. Forward pseudo section maps clearly demonstrate the relationship between dip angle, anisotropy coefficient and their anisotropic effect.

Key words： electrical properties of layered medium magnetotelluric anisotropy coefficient dip angle

Received: 04 July 2018 Published: 15 August 2019

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	Articles by authors
	Miao-Xin YANG
	Han-Dong TAN
	Sheng-Jun LIANG
	Xin WANG

Cite this article:

Miao-Xin YANG,Han-Dong TAN,Sheng-Jun LIANG, et al. Two-dimensional anomaly characteristics of the magnetotelluric method for a symmetrical anisotropic body[J]. Geophysical and Geochemical Exploration, 2019, 43(4): 794-803.

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https://www.wutanyuhuatan.com/EN/10.11720/wtyht.2019.1266 OR https://www.wutanyuhuatan.com/EN/Y2019/V43/I4/794

Resistivity model of the layered rock
a—rock in the actual situation;b—equivalent model

Anisotropy coefficient range of some rocks and strata

Survey region and element analysis
a—survey region;b—parent element and subunit

Thick plate model

The influence of different frequencies of the center point on the calculation results

The influence of different dip angles on the calculation results

The influence of different anisotropy coefficients on the calculation results

Section comparison figures of different dip angles and anisotropy coefficients of thick plate model

M type abnormal body model

Section comparison figures of different dip angles and anisotropy coefficients of M type abnormal body

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